GHSA-926M-QFG2-2W89

Vulnerability from github – Published: 2026-05-28 12:30 – Updated: 2026-05-28 12:30
VLAI
Details

In the Linux kernel, the following vulnerability has been resolved:

Bluetooth: hci_conn: fix potential UAF in create_big_sync

Add hci_conn_valid() check in create_big_sync() to detect stale connections before proceeding with BIG creation. Handle the resulting -ECANCELED in create_big_complete() and re-validate the connection under hci_dev_lock() before dereferencing, matching the pattern used by create_le_conn_complete() and create_pa_complete().

Keep the hci_conn object alive across the async boundary by taking a reference via hci_conn_get() when queueing create_big_sync(), and dropping it in the completion callback. The refcount and the lock are complementary: the refcount keeps the object allocated, while hci_dev_lock() serializes hci_conn_hash_del()'s list_del_rcu() on hdev->conn_hash, as required by hci_conn_del().

hci_conn_put() is called outside hci_dev_unlock() so the final put (which resolves to kfree() via bt_link_release) does not run under hdev->lock, though the release path would be safe either way.

Without this, create_big_complete() would unconditionally dereference the conn pointer on error, causing a use-after-free via hci_connect_cfm() and hci_conn_del().

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{
  "affected": [],
  "aliases": [
    "CVE-2026-46111"
  ],
  "database_specific": {
    "cwe_ids": [],
    "github_reviewed": false,
    "github_reviewed_at": null,
    "nvd_published_at": "2026-05-28T10:16:26Z",
    "severity": null
  },
  "details": "In the Linux kernel, the following vulnerability has been resolved:\n\nBluetooth: hci_conn: fix potential UAF in create_big_sync\n\nAdd hci_conn_valid() check in create_big_sync() to detect stale\nconnections before proceeding with BIG creation. Handle the\nresulting -ECANCELED in create_big_complete() and re-validate the\nconnection under hci_dev_lock() before dereferencing, matching the\npattern used by create_le_conn_complete() and create_pa_complete().\n\nKeep the hci_conn object alive across the async boundary by taking\na reference via hci_conn_get() when queueing create_big_sync(), and\ndropping it in the completion callback. The refcount and the lock\nare complementary: the refcount keeps the object allocated, while\nhci_dev_lock() serializes hci_conn_hash_del()\u0027s list_del_rcu() on\nhdev-\u003econn_hash, as required by hci_conn_del().\n\nhci_conn_put() is called outside hci_dev_unlock() so the final put\n(which resolves to kfree() via bt_link_release) does not run under\nhdev-\u003elock, though the release path would be safe either way.\n\nWithout this, create_big_complete() would unconditionally\ndereference the conn pointer on error, causing a use-after-free\nvia hci_connect_cfm() and hci_conn_del().",
  "id": "GHSA-926m-qfg2-2w89",
  "modified": "2026-05-28T12:30:29Z",
  "published": "2026-05-28T12:30:29Z",
  "references": [
    {
      "type": "ADVISORY",
      "url": "https://nvd.nist.gov/vuln/detail/CVE-2026-46111"
    },
    {
      "type": "WEB",
      "url": "https://git.kernel.org/stable/c/0beddb0c380bed5f5b8e61ddbe14635bb73d0b41"
    },
    {
      "type": "WEB",
      "url": "https://git.kernel.org/stable/c/1750a2df0eab61dc421a7afae74abdd239a44b85"
    },
    {
      "type": "WEB",
      "url": "https://git.kernel.org/stable/c/6823f730bf195fc296d9edd09e2ca94bc1ff5584"
    },
    {
      "type": "WEB",
      "url": "https://git.kernel.org/stable/c/dc34f8d8240f25dd137dc2758ebbcc75e3779142"
    },
    {
      "type": "WEB",
      "url": "https://git.kernel.org/stable/c/f8eaf92c57ad99358dd372580d5ff87623343a72"
    }
  ],
  "schema_version": "1.4.0",
  "severity": []
}


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